1. Field
The following description relates to an analog-to-digital (A/D) converter that may be used in an image sensor and a ramp signal generator that may be used in an A/D converter.
2. Description of the Related Art
A small sized high performance image sensor is widely used in various technical fields especially in the fields of image processing. Such an image sensor may be installed on digital cameras, camcorders, web cameras, security cameras, and the like, as well as mobile communication terminals.
The image sensor may convert an analog image received through a lens into digital signals. To perform the conversion, an analog-to-digital (A/D) converter is used. The A/D converter may use a reference signal to convert analog data into digital data, and the reference signal may vary based on the type of A/D converter. The reference signal may be easily affected by the electric power or circuit layout. Accordingly, errors may occur in the reference signal if electric power noise and circuit layout noise are input into the reference signal. These errors may cause the converted digital data to have errors thus degrading the image quality of a sensed image.